During the electrolysis of molten sodium chloride, the time required to produce `0.10 mol` of chlorine gas using a current of `3` amperes is

Options

A. 55 minutes
B. 110 minutes
C. 220 minutes
D. 330 minutes

Answer

B

Explanation

(b) Key Idea This problem is based on Faraday's first law of electrolysis which states that when an electric current is passed through an electrolytic solution, the amount of substance (w), deposited at the elecrtode, is proportional to the electric charge (q) passed through the electrolytic solution.
The formula used in the problem is
`w=(Eit)/(96500)`.....(i)
where,E=gram-equivalent mass of `Cl^(-)`
i=current, t=time, it =q
Given, w=0.01 mol `=(0.10xx71)g`,
`i=3A, E=35.5`
The following reactions occured,
At cathode: `2H_(2)O overset(+2e^(-)) to H_(2)+2OH^(-)`
At anode : ` underset(35.5 g )(2Cl^(-) overset(-2e^(-)) to underset(71g)(Cl_(2))`
Putting all values in expression (i) we get
`(0.10xx71)=(35.5)/(96500)xx3xxt or t=6433s`
`or t=107.22 min`
`~= 110 min " " [1s=(1)/(60)min]`